All Directional Ladder

ABSTRACT

An all directional ladder is provided having a base and a plurality of stair treads supported by and extending upwardly from the base at an angle. The ladder further includes a set of footpads, a retractable first and second set of wheels, and a third set of non-retractable wheels. The first and second set of wheels rotate 360° about a vertical axis to allow the ladder to be moved in any direction. A step lock assembly is positioned proximate the front of the base and a series of linkages are associated with this step lock assembly retracting the first and second set of wheels to change the ladder from a mobile position to a stationary position in which the ladder rests on the set of footpads and the third set of wheels. A kit and a method for retrofitting a ladder with an all directional movement system is also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to provisional application No. 60/905,121 filed on Mar. 6, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a mobile ladder, and, more particularly to a ladder having an all directional movement system incorporated therein and a kit for retrofitting an existing ladder with this all directional movement system.

2. Description of Related Art

U.S. Pat. Nos. 5,941,341; 6,039,147; and 6,962,233, all to Gillis et al., disclose a mobile ladder stand having a base, wheel sets proximate to the front, center, and rear of the base for enabling the ladder to move, a series of linkages for changing the ladder from a mobile position to a stationary position and vice versa, and footpads located proximate the base for supporting the ladder in the stationary position. The center wheel sets are designed so as to allow the ladder to pivot in place about the center of the base for changing the direction of the ladder.

U.S. Pat. No. 6,305,496 to Bieszczad discloses a mobile ladder stand having a base, a front wheel support, a first pair of swivable caster wheels mounted on the front wheel support, a rear wheel support located inwardly from the rear end of the base, a retractable second pair of swivable caster wheels mounted on the rear wheel support, and a third pair of nonswivable caster wheels mounted on the rear end of the base outwardly from the second pair of caster wheels. A plurality of footpads are mounted on the front end of the base forward of the first pair of caster wheels. The ladder stand is movable from a mobile position to a stationary position via a trip bar and movable back to the mobile position via a pair of independently operated foot pedals. The trip bar and foot pedals are coupled to a series of linkages, a trip tube, and a reset tube to enable movement between three separate modes of operation.

There is a need in the art for a mobile ladder incorporating an all directional movement system which has a minimum number of working components, is simple to manufacture, and can be readily retrofitted to an existing ladder.

SUMMARY OF THE INVENTION

The present invention has met these needs. According to a first aspect of the invention, an all directional ladder is provided comprising a base having a front, a center, and a rear and a plurality of stair treads supported by and extending upwardly from the base at an angle from the front to the rear thereof. The ladder further comprises a set of footpads extending from the front of the base, a retractable first set of wheels mounted proximate the front of the base, and a retractable second set of wheels mounted approximately midway between the center and the rear of the base. The first set of wheels and second set of wheels are mounted from a first and second set of casters adapted for rotating the first and second set of wheels, respectively. The casters preferably allow the wheels to rotate 360° to allow the ladder to be moved in any direction. A third set of wheels are mounted proximate the rear of the base. A step lock assembly is positioned proximate the front of the base and a series of linkages are associated with this step lock assembly and the first and second set of retractable wheels for retracting the first and second set of retractable wheels to change the ladder from a mobile position to a stationary position in which the ladder rests on the set of footpads and the third set of wheels.

According to a second aspect of the invention, a kit for retrofitting a ladder is provided wherein the kit comprises a first and second pair of axle rod receiving members adapted for attachment for the base, a first carriage assembly including a first axle rod adapted for placement within the first axle rod receiving member and a second carriage assembly including a second axle rod adapted for placement within the second axle rod receiving member. The first carriage assembly and the second carriage assembly include a first set of wheels mounted from a first set of casters and a second set of wheels mounted from a second set of casters, respectively. These first and second casters are adapted for rotating the first and second set of wheels, preferably 360°, to allow the ladder to move in any direction. The kit further includes a step lock assembly adapted for attachment proximate the front of the base and a series of linkages associated with the step lock assembly and the first and second carriage for retracting the first and second carriages and the first and second set of wheels to change the ladder from a mobile position to a stationary position in which the ladder rests on the set of footpads and the back set of wheels. The kit also includes adjustment members which allow the length between the first and second carriages to be adjusted according to the size of the ladder.

According to a third aspect of the invention, a method for retrofitting a ladder with an all directional movement system is provided using the kit discussed above. The all directional movement system of the invention is adaptable to a variety of ladders available in the marketplace having size adjustment capabilities depending upon the size and/or shape of the particular ladder be retrofitted.

These and other features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description with reference to the accompanying drawings, all of which form a part of the present invention, wherein like reference numerals designate corresponding parts in the various figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of an all directional ladder made in accordance with the present invention;

FIG. 2 is a rear perspective view of an all directional ladder made in accordance with the present invention;

FIG. 3 is a front elevational view of an all directional ladder made in accordance with the present invention;

FIG. 4 is a side elevational view of an all directional ladder made in accordance with the present invention;

FIG. 5 is a rear elevational view of an all directional ladder made in accordance with the present invention;

FIG. 6 is a top plan view of an all directional ladder made in accordance with the present invention;

FIG. 7 is a bottom plan view of an all directional ladder made in accordance with the present invention;

FIG. 8 is a side perspective view of an all directional ladder made in accordance with the present invention;

FIG. 9 is a side partial perspective view of a known type of rolling ladder having an all directional movement system kit made in accordance with the present invention attached thereto;

FIG. 10 is a side partial perspective view of a known type of rolling ladder having the all directional movement system made in accordance with the present invention attached thereto;

FIG. 11 is a partial perspective view of the rear portion of a ladder including the all directional movement system made in accordance with the present invention; and

FIG. 12 is a partial perspective view of the hardware that mechanically fastens the all directional movement system to a known type of rolling ladder.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, spatial or directional terms shall relate to the present invention as it is oriented in the drawing figures. However, it is to be understood that the present invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific components illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.

Reference is now made to FIGS. 1-8, which show an all directional ladder, generally indicated as 10, that includes a base 12 having a front 14, a center 16, and a rear 18. One type of a ladder base that can be used in the present invention is shown in the FIGS., however other ladder base designs can be used with the present invention. As particularly shown in the drawings, the base includes at least a pair of longitudinal members 22 joined by a front lateral member 24 which is mounted proximate the front 14 of the base 12 and a back lateral member 25 is mounted proximate the rear 18 of the base. One or more centrally located lateral members 26 can be provided on the base 12 at a location between the front and back lateral members 24, 25.

A plurality of stair treads 28 are supported by and extend upwardly from the base at an angle from the front 14 to the rear 18 thereof. These treads 28 are mounted to angled support strip members 30 and a series of support beams 32. Handles 34, as known in the art, may be provided on the ladder, such as by attachment to strip members 30.

A set of ladder feet 35 having footpads 36 positioned thereon extend from the front 14 of the base 12. These ladder feet 35/footpads 36 can include a pair of downwardly extending members fitted with a non-skid material, such as rubber pads, that contact the floor and prevent the ladder 10 from movement when such footpads 36 are in contact with the floor.

The ladder is fitted with an all directional movement system, generally indicated as 20. This all directional movement system 20 includes a retractable first set of wheels 38 mounted proximate the front 14 of the base 12. The first set of wheels 38 are mounted from a first set of casters 40 adapted for rotating the first set of wheels 38. Preferably, the first set of casters 40 are adapted for rotating the first set of wheels 38 360° about their vertical axis.

The system 20 further comprises a retractable second set of wheels 42 mounted between the center 16 and the rear 18 of the base 12 and, preferably, in close proximity to the rear 18 of the base 12. The second set of wheels 42 are mounted from a second set of casters 44 adapted for rotating the second set of wheels 42, also preferably 360° about their vertical axis. This 360° rotation of the first and second set of wheels 38, 42 allows the ladder 12 to be rotated and moved in any direction.

A third set of wheels 46 are mounted proximate the rear 18 of the base 12. This third set of wheels 46 may be mounted to a third set of casters 47, but this third set of casters 47 are rigid and do not allow the wheels 46 to rotate about their vertical axis.

A step lock assembly, generally indicated as 48, is positioned proximate the front 14 of the base 12. A series of linkages, generally indicated as 50, are associated with the step lock assembly 48 and the first and second set of retractable wheels 38, 42 for retracting the first and second set of retractable wheels 38, 42 to change the ladder 10 from a mobile position to a stationary position in which the ladder 10 rests on the set of footpads 36 and the third set of wheels 46. This stationary position enables the user to safely climb the ladder 12.

At least one foot lever 52 is associated with the series of linkages 50 such that an application of force thereto causes the first and second set of retractable wheels 38, 42 to pivot into an active position and lifting the feet 35 off the ground to change the ladder 12 from a stationary position to a mobile position. Once the ladder 12 is in the mobile position, the user is able to rotate and move the ladder 12 in any direction due to rotatability of the castors.

Referring particularly to FIGS. 1-2 and 7, the first set of casters 40 are attached to a first horizontally extending carriage assembly 54 positioned at the front 14 of the base 12. The second set of casters 44 are attached to a second horizontally extending carriage assembly 56 positioned approximately midway between the center 16 and the rear 18 of the base 12. The first and second carriage assemblies 54, 56 are connected to each other via a first vertically extending linkage 58, a second vertically extending linkage 60, and a longitudinally extending linkage 62 extending between the first and second vertically extending linkages 58, 60.

The first vertically extending linkage 58 is attached to a connecting member 64 which is associated with and activated by the application of a downward force to the step lock assembly 48. A step lock spring 66 is attached to the step lock assembly 48 to assist in the retraction of the first carriage assembly 54. Such step locks are well known in the prior art, for example, Tri-Arc Model nos. WLSR108246 and KDSR110246.

In operation, foot lever 52 is depressed causing the longitudinally extending linkage 62 to move the first and second carriages 54, 56 to cause the first and second set of wheels 38, 42 to engage the floor surface for all directional movement of the ladder 10. Once the ladder 10 is in place, the foot lever 52 is raised by applying pressure to the step lock assembly 48 so that the ladder 10 rests on the footpads 36 of the ladder feet 35 and the third set of wheels 46.

The longitudinally extending linkage 62 is, preferably, adjustable in length to adapt the series of linkages 50 to different sized ladders 10. This adjustability can be achieved by the provision of a series of apertures 68 extending along a length thereof and a pin 70 located on the second vertically extending linkage 60 adapted for cooperating with these apertures 68.

The first and second carriages 54, 56 can be secured to the ladder base 12 by any well known technique such as welding, mechanical attachment, and the like. An alternative attachment technique can be through a removable connection wherein the second carriage 56 includes a pair of axle rods 74 and the base 12 is fitted with a pair of axle rod receiving members 78. The axle rod 74 is then received within the axle rod receiving members 78 for mounting the second carriage 56 to the ladder base 12. The first carriage 54 is adapted to be supported by the front lateral member 24 proximate the front 14 of the ladder base 12. This support is achieved via the first vertical linkage 58 and the connecting member 64.

Referring to FIGS. 9-12, a second aspect of the invention is directed to a kit, generally indicated as 80, for retrofitting a ladder, generally illustrated as 100, with an all directional movement system, generally indicated as 20. Many elements of the retrofitting kit 80 are the same as those of the all directional ladder 10, discussed above. Therefore, like elements of the all directional assembly kit 80 with those of the all directional ladder 10 will be designated with the like reference characters.

This kit 80 may be adapted for use with any known type of ladder to mechanically fasten the all directional movement system 20 to an existing standard equipment ladder 100 to convert the standard equipment ladder 100 into an all directional ladder. This standard equipment ladder 100 preferably has a base 102 wherein the base includes a front 104, a center 106, and a rear 108, a set of footpads 36 extending from the front 104 of the base 102 and a back set, or “third set” of wheels 46 mounted proximate the rear 108 of the base 102. An example of a known ladder design is the Tri-Arc Model # KDSR 108246, which is shown in FIG. 9.

The kit 80 includes a pair of axle rod receiving members 78, which are adapted for attachment to the base 102. A pair of kit plates 84, as shown in FIG. 12, are mechanically attached, such as by bolts, screws, and the like 86, to the rear 108 of the base 102. In particular the plates 84 can be attached to the third set of casters 47. The pair of axle rod receiving members 78 are mounted on the pair of kit plates 84. A first carriage assembly 54 is provided. This first carriage assembly 54 includes a first set of wheels 38 mounted from a first set of casters 40 adapted for rotating the first set of wheels 38, preferably 360° about a vertical axis. The first carriage assembly 54 is supported by front lateral member 24, as discussed above. A second carriage assembly 56 is provided including an axle rod 74 adapted for placement within the pair of axle rod receiving members 78. The second carriage assembly 56 includes a second set of wheels 42 mounted from a second set of casters 44 adapted for rotating the second set of wheels 42, also preferably 360° about a vertical axis. This 360° rotation of the first and second set of wheels 38, 42 allow the ladder 100 to be moved in an infinite number of directions.

Axle stop clamps 82 are provided to maintain the position of the axle rod 74 within the pair of axle rod receiving members 78. The pair of axle rod receiving members 78 may also include bushings (not shown) for receiving the axle rod 74.

The kit 80 further includes a step lock assembly 48 adapted for attachment proximate the front 104 of the base 102. A series of linkages, generally indicated as 50 are associated with the step lock assembly 48 and a first and second carriages 54, 56 for retracting the first and second carriages 54, 56 and the first and second set of wheels 38, 42 to change the ladder 10 from a mobile position to a stationary position in which the ladder rests on the set of footpads 36 and the back or third set of wheels 46. The series of linkages 50 include a first vertically extending linkage 58, a second vertically extending linkage 60, and a longitudinally extending linkage 62 extending between the first and second vertically extending linkages 58, 60. The first vertically extending linkage 58 is attached to a connecting member 64 which is associated with and activated by the application of a downward force to the step lock assembly 48.

The series of linkages 50 are discussed in further detail above in reference to the all directional ladder 10. Also, as discussed above, the longitudinally extending linkage 62 is adjustable in length via a series of apertures 68 and pin 70 arrangement to adapt the movement system to different sized ladders.

At least one foot lever 52 is associated with the series of linkages 50 wherein an application of force thereto causes the first and second carriages 54, 56 to pivot into an active position to change the ladder 100 from a stationary position to a mobile position.

According to a third aspect of the invention, there is provided a method of retrofitting a ladder 100 with an all directional movement system 20 to a known type of ladder 100 including a base 102 having a front 104, a center 106, and a rear 108. The ladder 100 includes a set of footpads 36 extending from the front 104 of the base 102, and a back or third set of wheels 46 mounted proximate the rear 108 of the base 102.

The method includes the steps of mechanically securing a pair of axle rod receiving members 78 to the base 102 via a pair of kit plates 84 and providing a first carriage assembly 54 including a first set of wheels 38 mounted from a first set of casters 40 adapted for rotating the first set of wheels 42. The first carriage assembly 54 is supported by front lateral member 24. The method further includes providing a second carriage assembly 56 including the second set of wheels 42 mounted from a second set of casters 44 adapted for rotating the second set of wheels 42. The second carriage assembly 56 includes an axle rod 74 extending across the length of the second carriage assembly 56. The method also includes, inserting opposing ends of the second axle rod 74 into the pair of axle rod receiving members 78, securing a step lock assembly 48 proximate the front 104 of the base 102, and providing a series of linkages 50 adapted for coacting with the step lock assembly 48 and the first and second carriages 54, 56 for retracting the first and second carriages 54, 56 and the first and second set of wheels 38, 42 to change the ladder 100 from a mobile position to a stationary position in which the ladder 100 rests on the set of footpads 36 and the back or third set of wheels 46. A foot lever 52 is associated with the step lock assembly 48 to convert the ladder from a stationary position to a mobile position.

The series of linkages 50, the step lock assembly 48, the foot lever 52, and the operation of changing the ladder from mobile to stationary positions and from stationary to mobile positions is discussed in detail above.

It will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed in the foregoing description. Accordingly, the particular embodiments described in detail herein are illustrative only and are not limiting to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof. 

1. An all directional ladder comprising: a base having a front, a center, and a rear; a plurality of stair treads supported by and extending upwardly from the base at an angle from the front to the rear thereof; a set of footpads extending from the front of the base; a retractable first set of wheels mounted proximate the front of the base, said first set of wheels mounted from a first set of casters adapted for rotating the first set of wheels; a retractable second set of wheels mounted approximately between the center and the rear of the base, said second set of wheels mounted from a second set of casters adapted for rotating the second set of wheels; a third set of wheels mounted proximate the rear of the base; a step lock assembly positioned proximate the front of the base; and a series of linkages associated with the step lock assembly and the first and second set of retractable wheels for retracting the first and second set of retractable wheels to change the ladder from a mobile position to a stationary position in which the ladder rests on the set of footpads and the third set of wheels.
 2. The all directional ladder as claimed in claim 1, including at least one foot lever associated with the series of linkages such that an application of force thereto causes the first and second set of retractable wheels to pivot into an active position to change the ladder from a stationary position to a mobile position.
 3. The all directional ladder as claimed in claim 1, wherein the first and second set of casters are adapted for rotating said first and second set of wheels 360° such that said ladder is adapted for movement in any direction.
 4. The all directional ladder as claimed in claim 1, wherein the first set of casters are attached to a first horizontally extending carriage assembly positioned at the front of the base and the second set of casters are attached to a second horizontally extending carriage assembly positioned approximately midway between the center and the rear of the base.
 5. The all directional ladder as claimed in claim 4, wherein said first and second carriage assemblies are connected to each other via a first vertically extending linkage, a second vertically extending linkage, and a longitudinally extending linkage extending between said first and second vertically extending linkages.
 6. The all directional ladder as claimed in claim 5, wherein the first vertically extending linkage is attached to a connecting member which is associated with and activated by the application of a downward force to the step lock assembly.
 7. The all directional ladder as claimed in claim 5, wherein the longitudinally extending linkage is adjustable in length.
 8. The all directional ladder as claimed in claim 1, wherein said first set of wheels and said first set of casters are mounted onto a first carriage assembly and said second set of wheels and said second set of casters are mounted onto a second carriage assembly and wherein said second carriage member is adapted to be received within a pair of rod receiving members mounted proximate the rear of the base.
 9. A kit for retrofitting a ladder with an all directional movement system, said ladder including: a base having a front, a center, and a rear; a set of footpads extending from the front of the base, and a back set of wheels mounted proximate the rear of the base, said kit comprising: a pair of axle rod receiving members adapted for attachment to the rear portion of the base; a first carriage assembly including a first set of wheels mounted from a first set of casters adapted for rotating the first set of wheels, said first carriage assembly adapted to be supported by a front lateral member mounted proximate to the front of the base of the ladder; a second carriage assembly including an axle rod adapted for placement within said pair of axle rod receiving members, said second carriage assembly including a second set of wheels mounted from a second set of casters adapted for rotating the second set of wheels; a step lock assembly adapted for attachment proximate the front of the base; and a series of linkages associated with the step lock assembly and the first and second carriage for retracting the first and second carriages and the first and second set of wheels to change the ladder from a mobile position to a stationary position in which the ladder rests on the set of footpads and the back set of wheels.
 10. The kit as claimed in claim 9, including a pair of kit plates having said pair of axle rod receiving members mounted thereon, said pair of kit plates as adapted for mechanical attachment proximate the rear of the base.
 11. The kit as claimed in claim 9, including at least one foot lever associated with the series of linkages wherein an application of force thereto causes the first and second carriages to pivot into an active position to change the ladder from a stationary position to a mobile position.
 12. The kit as claimed in claim 9, wherein the first and second set of casters are adapted for rotating said first and second set of wheels 360° such that said ladder is adapted for movement in any direction.
 13. The kit as claimed in claim 9, wherein said first and second carriage assemblies are connected to each other via a first vertically extending linkage, a second vertically extending linkage, and a longitudinally extending linkage extending between said first and second vertically extending linkages.
 14. The kit as claimed in claim 13, wherein the first vertically extending linkage is attached to a connecting member which is associated with and activated by the application of a downward force to the step lock assembly.
 15. The kit as claimed in claim 13, wherein the longitudinally extending linkage is adjustable in length to adapt the movement system to different sized ladders.
 16. The kit as claimed in claim 15, wherein the longitudinally extending linkage includes a series of apertures extending along a length thereof and the second vertically extending linkage includes a pin adapted for cooperating with said apertures.
 17. A method of retrofitting a ladder with an all directional movement system, said ladder including: a base having a front, a center, and a rear; a set of footpads extending from the front of the base; and a back set of wheels mounted proximate the rear of the base, said method comprising; securing a pair of axle rod receiving members onto said base; providing a first carriage assembly including a first set of wheels mounted from a first set of casters adapted for rotating the first set of wheels, said first carriage assembly adapted for contacting a front lateral member mounted proximate to the front of the base of the ladder; providing a second carriage assembly including a second set of wheels mounted from a second set of casters adapted for rotating the second set of wheels, said second carriage assembly including an axle rod extending across the length of the second carriage assembly; inserting opposing ends of said axle rod into said pair of axle rod receiving members; securing a step lock assembly proximate the front of the base; and providing a series of linkages adapted for coacting with said step lock assembly and the first and second carriages for retracting the first and second carriages and the first and second set of wheels to change the ladder from a mobile position to a stationary position in which the ladder rests on the set of footpads and the back set of wheels.
 18. The method of claim 17, wherein said pair of axle rods are secured to a pair of kit plates and the back set of wheels are mounted from a third pair of casters and the method includes mechanically securing the kit plates to the pair of caster plates.
 19. The method of claim 17, wherein the series of linkages include a longitudinally extending linkage extending between said first and second carriage assemblies, said method including providing a series of apertures adapted for coacting with a pin member for adjusting the length between the first and second carriages according to the size of the ladder. 